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boiler with tankless hot water with additional water take

rkuz Member Posts: 1
have a separate hot water storage unit with a tank less boiler. the boiler is always running even when no one is using hot water.  Is there a way to make the storage unit the direct unit and plug up the tank less system


  • heatpro02920
    heatpro02920 Member Posts: 991
    Can you add a pic?

    I take it you have an electric water tank with a potable water circulator circulating water through your tankless coil for storage?   If so you can "plug up the tankless {or just shut it off, depending on how its piped} and run the electric water heater, but that will probably cost more than running the oil burner...

    Maybe we can help with why the burner is constantly running? 

    Is the aquastat for the tank set to 30* less than the boiler limit? Sometimes the boiler limit is 160 and the tank is set to circulate to 140 {sometimes higher} but the problem is by the time the heat transfers from the boiler to the tankless than from the tankless to the tank you can only get 130 so it just runs constant when it cant satisfy the tank, BUT this depends on a few factors...  After a while the tank should slow down sucking heat out of the boiler when it gets to its max temp...  {hope I said that rite}...

    Another thing to consider is that in the summer when you are not using heat you can turn down your limits, this takes some trial and error, but I have customers that have a tankless/tank setup that turn their high temp down to 140 for the summer....
  • icesailor
    icesailor Member Posts: 7,265
    Tankless/storage tanks:

    If what you have is what I install and have in all my houses, the main burner control should be a triple acting controller with a "High Limit" and a "Operating Control". The "Operating Control" must be set at a minimum of 20 degrees below the high limit. If the operating control is set at 140 degrees, you will not get condensing in the flue passages.

    The water heater storage tank is usually set at 125 degrees. The lower thermostat on the tank controls the circulator. It should nor directly control the burner.

    I find that some who come here for information , have an obsession about running burners. Burners run to make heat. That's what they are supposed to do. Every time they hear the burner running, they have a panic attack like someone has their hand in their bank account.

    Post pictures of this equipment. I'm sure that it doesn't run any where as much as you describe and if it does, there's something wrong with the adjustments or the installations.
  • billtwocase
    billtwocase Member Posts: 2,385
    running often

    It may also be running for heat. It does both. Pics will help. What are your control settings?
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